• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.172-183
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• 2012

In 2011, floods were at the worst stage of devastation in Chao Phraya river basin of Thailand. The purpose of this study is to trace the flood inundation area around Chao Phraya river basin by using Terra MODIS image because it has the ability of spatiotemporal dynamics. The MODIS indices, which included the enhanced vegetation index(EVI), land surface water index(LSWI), and the difference in the values of EVI and LSWI(DVEL), were extracted from MODIS product MOD09 8-day composite datasets with a spatial resolution of 500m from Jul. 29, 2011 to Jan. 09, 2012. We found that combined application of EVI, LSWI, and DVEL was suitable for monitoring flood inundation. For the extracted flood inundation area and water-related area. The result can be used to acquire the flood inundation data scattered and demonstrate the potential for the use of MODIS data for temporal and spatial detection of flood effects.

• Proceedings of the KSRS Conference
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• v.2
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• pp.563-566
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• 2006

In order for the evaluation and analysis of the spring drought which has been periodically occurring in Korean peninsula since 2000, the use of satellite image data is increasing to investigate temporal and spatial characteristics of the drought areas. The recent spring droughts in south Korea have some characteristics. It last for short period in spring when the activity of vegetation is not lively and it have large areal deviation in the severity of drought. In this study, considering the characteristics of the spring drought in Korean peninsular, the MODIS satellite image data which has superior spatial and radiometric resolutions was used for the analysis of the spring drought. In two basins having different spatial characteristics, the drought events were selected and their severities were analyzed using the MODIS NDVI, LSWI, and daily rainfall data since 2000, and the spatial characteristics of the drought area were analyzed using the DEM, land cover, and digital forest map of the study areas.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.4
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• pp.176-192
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• 2006

The need for a systematic drought management has increased since last countrywide drought in 2001. Naturally various studies for establishing drought plan and preventing drought disaster have been conducted. MODIS image provided by Terra satellite has effective spatial and temporal resolutions to observe spatial and temporal characteristics of a region. MODIS data products are easy for preprocessing and correcting geometrically and provide various data set in regular which are applicable for drought monitoring. In this study, Ansung river and the upstream of South Han river basin was chosen for case study to identify and assess spring drought. The multi-period MODIS image and accumulated precipitation were used to detect not only the drought year but also the vegetation change of normal year and the result were compared with various spatial data. The result shows NDVI and LSWI with is more appropriate than LST for assesing spring drought in Korea and two month cumulative precipitation has moderate relationship with drought. It is necessary to use MODIS image which has same period and same space for effective drought analysis because drought is also affected by landover and altitude.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.256-256
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• 2012

2011년 태국 차오프라야 강 유역($160,813km^2$)에서 발생한 홍수에 의해 많은 피해가 발생했다. 태국 홍수는 2011년 7월 말부터 3개월간 내린 집중호우로 중부지방에 50년 만에 최악의 자연재해를 맞이하였다. 태국 북쪽 지역에서 난 강과 핑 강의 범람을 시작으로 태국 중앙 지역을 흐르는 차오프라야 강의 수위는 상류의 홍수가 하류로 내려옴에 따라 범람하여 수도 방콕까지 침수되었다. 본 연구에서는 홍수범람시 시공간적 침수상황이 파악 가능한 Terra MODIS (Moderate Resolution Imaging Spectroradiometer) 영상을 이용하여 태국 차오프라야 강 유역의 홍수에 의한 침수지역을 추정하고자 하였다. 2011년 7월 29일에서 2012년 1월 9일까지의 500 m 해상도인 MODIS product MOD09 (Surface Reflectance) 8일 합성 영상을 수집하고 식생지수 (EVI; Enhanced Vegetation Index), 지표수분지수 (LSWI; Land Surface Water Index))와 DVEL지수 (Difference Value between EVI and LSWI)를 이용하여 홍수범람 지역과 수역관련지역을 정보화 기법을 제시하였다. 본 연구의 결과는 홍수 범람지역의 자료를 정보화하고 그 결과를 정량적으로 제시하는 방법으로 활용될 수 있으며, MODIS 자료의 이용은 시공간적 하천 홍수범람지역 탐지의 가능성을 알 수 있었다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.2
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• pp.69-78
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• 2011

Rice is one of the world's staple foods. Paddy rice fields have unique biophysical characteristics that the rice is grown on flooded soils unlike other crops. Information on the spatial distribution of paddy fields and the timing of irrigation are of importance to determine hydrological balance and efficiency of water resource management. In this paper, we detected the timing of irrigation and spatial distribution of paddy fields using the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the NASA EOS Aqua satellite. The timing of irrigation was detected by the combined use of MODIS-based vegetation index and Land Surface Water Index (LSWI). The detected timing of irrigation showed good agreement with field observations from two flux sites in Korea and Japan. Based on the irrigation detection, a land cover map of paddy fields was generated with subsidiary information on seasonal patterns of MODIS enhanced vegetation index (EVI). When the MODISbased paddy field map was compared with a land cover map from the Ministry of Environment, Korea, it overestimated the regions with large paddies but underestimated those with small and fragmented paddies. Potential reasons for such spatial discrepancies may be attributed to coarse pixel resolution (500 m) of MODIS images, uncertainty in parameterization of threshold values for discarding forest and water pixels, and the application of LSWI threshold value developed for paddy fields in China. Nevertheless, this study showed that an improved utilization of seasonal patterns of MODIS vegetation and water-related indices could be applied in water resource management and enhanced estimation of evapotranspiration from paddy fields.